As much as I hate to say it like this, a pandemic is only going to kill something like 5% of the population at the top end. The Spanish flu in 1918 infected 500 million people, which was 27% of the population (according to Wikipedia). The death toll was about 40-50 million (possibly up to 100 million at worst). It was one of the most deadly worldwide infections in the history of the world, but probably killed less than 3% of the population.

A pandemic is going to severely hurt the economy, but it won't completely stop it. It will not be the case that nothing will be produced for months on end. People will go to work. Farmers will produce food. There will be shops. But things will also be in short supply. Prices will probably rise. Poor people will be hit harder and there will probably be some famine (or at least more than there is now). But things will still continue.

In an event like an earthquake, entire distribution lines are shut down because you can't physically get somewhere. With a pandemic, things will be in short supply because labour is in short supply.